The objective of this research is to synthesize new types of carbon-functional organoboron compounds, especially pyrimidine and amino acid mimics, designed for possible utility in either or both of two approaches to cancer treatment. One approach is the boron-10 neutron capture therapy of brain tumors, for which localization and binding of a sufficient amount of boron in nontoxic form in the tumor is required. Water-soluble compounds containing biologically related functional groups together with a high proportion of boron seem the most likely candidates, and new compounds will be submitted to A.H. Soloway, Northeastern University, for testing in tumor-bearing mice. The other approach is the possible use of boron compounds as antimetabolites for cancer chemotherapy, since boron can serve as a pseudo-carbon atom in certain purine, pteridine, or amino acid analogs. Methanetetraboronic esters, C(B(OR)2)4, and the derived triborylmethide anions, ((RO)2B)3C, will be used to introduce boron into appropriate structures. The anion undergoes alkylation by alkyl halides, condensation with aldehydes or ketones, and other reactions suitable for this purpose. On the basis of recent findings, routes to pyrimidine and amino acid analogs can be outlined with confidence. In another phase of this work, syntheses of carborane-substituted pyrimidines are planned, based on known aspects of carborane and pyrimidine chemistry.